Rotary device



May 21, 1968 R. T. BECKER ET AL 3,384,321

ROTARY DEVICE Filed Jan. 19, 1966 4 Sheets-Sheet 1 INVENTORS 00652 7? 55cm? a M44 MM ,6 .eaczae ROTARY DEVICE 4 Sheets-Sheet 2 'riled Jan. 19, 1966 y 1968 R. T. BECKER ET AL 3,384,321

ROTARY DEVICE 4 Sheets-Sheet 3 Filed Jan. 19, 1966 ANVENTORS E062)? I ff/Fil IVA [A444 A. 156K166]? Mww May 21, 1968 R. T. BECKER ET AL ROTARY DEV I CE 4 Sheets-Sheet 4 l-iled Jan. 19, 1966 nMMMINE W w ffi 5. M MM mm W BY WW United States Patent 3,384,321 ROTARY DEVICE Roger T. Becker, Kalamazoo, and William K. Becker,

Ross Township, Kalamazoo County, Micl1., assignors to Aero-Motive Manufacturing Company, Kalamazoo,

Mich, a corporation of Michigan Filed Jan. 19, 1966, Ser. No. 521,729 22 Claims. (Cl. 242107.5)

ABSTRACT OF THE DISCLOSURE A rotary device, such as a balance reel, which is capable of opposing a torque applied thereto and which is comprised of a frame structure and a torque-receiving means, such as a drum, rotatably supported upon the frame structure. One or more spring motor means are mounted on the frame structure and coupling means are provided for connecting one end of the spring means to the frame structure and the other end of the spring means to the torque-receiving means. Additional spring motor means may be connected in parallel between the torque-receiving means and the frame structure.

This invention relates in general to a rotary device having a torque receiving member and mechanism attached thereto for opposing a torque applied to said member and, more particularly, to a balance reel having motor means comprising a plurality of separable spring motors which can be used individually or in parallel to balance a wide range of loads.

By way of illustration, reference is specifically made hereinafter to balance reels because the invention developed out of efforts made to improve the utility and performance of balance reels. However, it will be apparent that the invention has other applications outside of the field of reels.

It is known that balance reels are widely used for supporting relatively heavy loads, such as engine parts, which are being moved along a production line while a series of operations are performed thereon. It is often desirable to move structures of widely different weights along the same production line at different times, but conventional balance reels are not normally capable of being adjusted for such wide variations in weight. That is, while the spring tension can be adjusted on some balance reels to accommodate minor variations in weight, it is generally necessary to change the entire balance reel if a big change in load must be accommodated. Alternatively, the reel can be dismantled so that a spring or spring having stronger (or weaker) tension can be mounted in the reel housing in place of the previous springs, but this requires much time and added expense.

Thus, there has long been the need for a sati factory balance reel capable of quick, easy and inexpensive adaptation to large changes in load capacity, such as changes involving more than 100 percent of one selected load capacity.

It has also been recognized that the springs in typical spring motors tend to fatigue in time and sometimes even break. However, as indicated above, the replacement of such springs on existing balance reels in a time-consuming and often difficult job, which is usually not undertaken until absolutely necessary. That is, spring motors are often used after it is evident that they are fatioued and, therefore, may fail in use. On the other hand, if it were a simple job to change the springs, or the entire motor, inexpensively, the amount of failures could be reduced by more frequent changes of the springs or motors. Thus, there has been a known and serious need for a balance reel wherein the changing of the spring and/or spring 3,334,321 Patented May 21, 1968 "ice motor would be so easy as to encourage changing thereof before a failure is likely.

Accordingly, the objects of this invention are to provide:

(1) An improved balance reel having spring motor means capable of easy and quick adjustment to accommodate the balance reel to a Wide range of loads without materially increasing the cost beyond that which would be required for a conventional balance reel having the same maximum capacity.

(2) A balance reel, as aforesaid, having motor means comprising a plurality of spring motor units capable of being coupled together quickly and easily to prov de a wide range of different powers.

(3) A balance reel, as aforesaid, in which each of the spring motors is substantially identical and interchangeable.

(4) A balance reel, as aforesaid, in which each of sa d spring motors has means for automatically stopping r0- tation thereof in a direction which will effect unwinding of the drum if the motor spring fails.

(5) A balance reel, as aforesaid, which can be manufactured economically, which is convenient and easy to operate, which is foolproof in operation, and which can be maintained with a minimum of time and effort.

Other objects and purposes of this invention will become apparent to persons familiar with this type of equipment upon reading the following specification and examining the accompanying drawings, in which:

FIGURE 1 is a rear end elevational view of a balance reel embodying the invention.

FIGURE 2 is a broken sectional view substantially as taken along the line II-II in FIGURE 1.

FIGURE 3 is a sectional view taken along the line III-III in FIGURE 2.

FIGURE 4 is a front end view of said balance reel.

FIGURE 5 is an exploded central, cross-sectional view of one of the spring motors shown in FIGURE 2.

FIGURE 6 is a perspective View of a spring motor housing.

FIGURE 7 is a sectional view taken along the line VII-VII in FIGURE 2.

FIGURE 8 is a sectional view taken along the line VIIIVIII in FIGURE 4.

FIGURE 9 is a sectional view taken along the line IX-IX in FIGURE 2.

For convenience in description, the terms upper, lower and words of similar import will have reference to the balance reel of the invention as appearing in FIG- URE 1. The terms front, rear and words of similar import will have reference to the left and right ends, respectively, of the balance reel as appearing in FIGURE 2. The terms inner, outer and derivatives thereof will have reference to the geometric center of said balance reel and parts thereof.

General construction The objects and purposes of the invention, including those set forth above, have been met by providing a balance reel having a frame structure, a conical drum upon which a flexible element is wound and shaftmeans for supporting the drum on the frame structure. The balance reel also has a motor unit comprised of a plurality of spring motors which are mounted upon the frame structure and which can be coupled together in various combinations to provide a variety of motor units capable of providing balanced support for a wide range of loads. In a preferred embodiment, said spring motors are substantially identical and interchangeable. The spring motors are coupled in parallel and the balance reel is equipped with mechanism for making minor tension adjustments in the motor unit.

Detailed description The balance reel (FIGURES 1 and 2), which has been selected to illustrate a preferred embodiment of the invention, is comprised of a frame structure 11 including a drum housing 12 and a hanger device 13 adjustably mounted upon the housing for engagement with a support structure of any conventional type, such as a hook 14 on a conveyor 15 (FIGURE 4).

The balance reel 10 includes a drum 16 (FIGURE 2), which is conical in this embodiment and is rotatably supported within the housing 12 by means of the main shaft 17. Said housing 12 includes a cup-shaped portion 18 having a substantially conically shaped drum chamber 19 which is closed at its rearward end by a substantially fiat and circular end plate 22. The drum housing 12 also has a gear chamber 23 which communicates with the small end of the drum chamber 19.

The drum 16 is also substantially cup-shaped and has a spiral groove 24 in the periphery thereof for reception of a cable 26 which is anchored upon said drum near the radially larger end thereof in a substantially conventional manner, the other end of said cable extending downwardly through an appropriate opening in the abutment 27 on the lower side of the housing 12 for engagement with a load 28 (FIGURES 1 and 4).

The drum 16 is concentrically disposed in the chamber 19 and it has at its small end an axial end wall 29 which is rotatably mounted upon the shaft 17 by the bearing 32. An end plate 33 covers the large, open end of the drum 16 and it has an outer edge 34 which extends radially beyond said cup-shaped portion and which has spaced recesses 36 into which the stop element 37 may be urged if it becomes desirable to lock the drum 16 against rotation. Specifically, the lever 38 (FIGURES 4 and 8), which is pivotally attached to the stop element 37 by the pin 39 can be pivoted into a position whereby it permits the spring 42 to move the stop element 37 rightwardly against said edge 34.

The end plate 33 (FIGURE 2) is rigidly secured to the cup-shaped portion 25 by the bolts 43 and to an external hub 44 by means of the bolts 46. The hub 44 is rotatably supported upon the end plate 22 by means of the bearing 49 which is seated in the central opening 48 in the end plate 22. The shaft 17 is rotatably supported within the hub 44 by the sleeve bearing 47.

An adjustable friction brake 52 is mounted upon the front side of the portion 18 of the housing 12 and part thereof is disposed in the gear chamber 23. Said brake 52 includes a shoe 53 which is pressed against the end wall 29 of the drum 16 by the pressure member 55. An adjustment screw 56 is threadedly received through the end wall 54 of the housing 12 for engagement with one end of a spring 57 which is thereby adjustably held under compression against the axial end wall 58 of the pressure member 55.

A worm gear 61 (FIGURE 2) is supported upon the shaft 17 within the gear chamber 23 and held against rotation with respect thereto by the key device 62. A worm 63, which engages the worm gear 61, is supported upon the worm shaft 64, which extends through the wall portion 18 of the housing 12. Said shaft 64 has a head 66 on its outer end for engagement by a conventional tool to effect rotation of the gear 61, hence the shaft 17, for reasons appearing hereinafter.

The front end of the shaft 17 (FIGURE 2) is snugly, but rotatably, disposed within a central opening 67 in the end wall 54. The rear end of the shaft 17 is preferably flush with the rearward side of the hub 44 and has an out-of-round, here square, recess 68 opening rearwardly.

A star wheel 71 (FIGURES 2 and 9) is rotatably supported upon the bolt shank 72 which is in turn received through an opening 73 in the end plate 33 for engagement by a nut 74. The star wheel 71 (FIGURE 9) has uniformly spaced projections 76 which define notches into which the roller 78 on the pin 79 is successively received as the drum 16 is rotated. The star Wheel 71 and roller 78 operate substantially in the manner of a Geneva wheel mechanism for the purpose of positively limiting the number of rotations which the drum 16 is permitted to make. That is, the star wheel 71 has a limited rotational movement of less than 360 degrees and, when it reaches such limit, the drum 16 is locked by said star wheel against further rotation. The locking occurs just before the cable 26 is completely unwound from the drum and, also, just before the cable is completely wound upon the drum.

The motor unit 82 (FIGURE 2) is, in this particular embodiment, comprised of three substantially identical spring motors 83, 83A and 83B. The spring motor 83, for example, includes a substantially cylindrical cupshaped housing 84 having a peripheral wall 86, and one axial end wall 87 with a central opening 88. The open edge of the peripheral wall has an annular notch 91 into which an annular ridge 92 on the rear face of the end plate 22 is snugly and slideably received. The cup-shaped portion 18 and the end plate 22 have radially extending and alignable ears 93 and 94 with openings 96 and 97, respectively, through which the screws 98 are received for securing the plate 22 upon the cup-shaped portion 18. Each pair of ears 93 and 94 also has a combined opening 99 alignable with an opening 102 in a radially projecting ear 103 on the housing 84 adjacent the notch 91. A bolt 104 is received through the openings 102 and 99 for the purpose of securing the housing 84 with respect to a frame structure 11.

In a preferred embodiment (FIGURE 2), there are three uniformly spaced ears 93, 94 and 103 on the housing portion 18, end plate 22 and housing 84, respectively. The housing 84 also has three uniformly spaced ears 106 at the rearward end thereof and radially outwardly of the end wall 87, and these ears are preferably disposed intermediate the ears 103 circumferentially of the peripheral wall 86. This arrangement facilitates insertion of the bolts 104 through the ears 93, 94 and 103 and the insertion of the bolts 104A through the ears 103A on the motor housing 84A and the ears 106 on the motor housing 84. The openings 99 in the cars 93 and 94, and the openings 108 in the ears 106 are preferably threaded, whereas the openings 102 and 102A in the ears 103 and 103A are preferably smooth bore, but other arrangements are contemplated.

A sleeve bearing 109 is disposed within the opening 88 in the end wall 87 for rotational engagement with the hub 112 which is rigidly secured by the rivets 113 to one side plate 114 of the spring retainer 116. Another side plate 117 is connected to and spaced from the side plate 114 by a plurality, here four, of parallel, uniformly spaced studs or cross rods 113. In this particular embodiment, one end of each cross rod 118 (FIGURES 2 and 5) is rigidly secured to the side plate 114 and the other end is threaded and extends through an opening 121 in the side plate 117 for engagement by a nut 122. The retainer 116 and hub 44 combine to provide an outer coupling device between the spring 138 and the drum 16.

One end of a stub shaft 123 is rotatably supported by the sleeve bearing 124 within the opening 126 in the hub 112. The other end of said shaft has an out-of-round extension 127, which is preferably of square cross section in this particular embodiment and which is snugly and slideably received into the square recess 68 in the main shaft 17 whereby rotation of the main shaft 17 will effect rotation of the stub shaft 123. The rearward or outer end of the hub 44 has an axial projection 128 which is out-ofround, preferably square, for snug, slideable reception into a corresponding square opening 129 in the side plate 117, when said extension 127 is properly disposed within the square recess 68. Accordingly, since the drum 16 is rigidly secured to the hub 44 by the bolts 46, rotation of the drum 16 also effects rotation of the spring retainer or cage 116 with respect to the shaft 17 and stub shaft 123.

A pair of preferably identical collars 132 and 133 are secured to the stub shaft 123 by means of the pins 134 (FIGURE 3). Each of said collars has a tangentially opening recess 136 into which the hook 137 at the inner end of the coil spring 138 is removably received for anchoring same. The two collars I32 and 133, which could be replaced by a single collar, combine with the stub shaft 123 to provide an inner coupling device between the spring 138 and the main shaft 17. The outer end of the spring 138 is provided with a hook 139 which is receivable into a notch 142 in the pawl 143 which is pivotally supported upon a cross rod 118. The pawl 143 is normally held by the spring 138 in its solid line position of FIGURE 3.

A spiral spring 144 (FIGURE 5), which encircles the cross rod 118, is secured at one end to the pawl 143 and at the other end to the cross rod 118 so that the spring 144 urges the pawl 143 toward its broken line position of FIGURE 3. Thus, if spring 138 fails, spring 144 will pivot the pawl 143 almost instantaneously into engagement with one of the abutments 146 projecting from the inner surface of the peripheral wall 86. For further details with respect to a safety device of this type, reference is made to the disclosures in Patent No. 3,105,652.

The foregoing, detailed structure set forth above with respect to the spring motor 83 also applies to the corresponding parts of the spring motors 83A and 83B. Accordingly, when three spring motors 83, 83A and 83B are interconnected according to the teachings of the invention, the springs 138, 138A and 1388 thereof are anchored at their inner ends upon the shaft assembly including the main shaft 17 and the stub shafts 123, 123A and 123B. The outer ends of said springs are anchored with respect to the cages 116, 116A and 1163, respectively, which are interconnected for simultaneous rotation with the drum 16. Thus, the springs 138, 138A and 138B are connected in parallel to resist resiliently rotation of the drum 16 in the unwinding direction thereof. Moreover, the stub shafts and their attached collars serve as a combined inner coupling means and the spring retainers serve as an outer coupling means. The collars 132, 133 can be omitted and the spring 138 can be attached to the stub shaft 123, and/or the pawl 143 can be omitted and the spring 138 can be attached to the rod 118. The main shaft 17 may, under some circumstances, be rigidly connected to the housing 12.

A circular end disk 151 (FIGURE 1) is provided with radially extending ears 152 through which bolts 153 are received for the purpose of mounting said disk 151 upon the rearward end of the motor housing 84B to cover the end wall 87B, the hub 112B and the exposed end of the stub shaft 123B.

It will be seen that, although the spring motors 83, 83A and 83B are disclosed as substantially identical in this particular embodiment of the invention, one of said spring motors could, without departing from the scope of the invention, have a housing, spring retainer and stub shaft which are substantially and axially longer or shorter than the corresponding parts in the spring motor 83, for example, to accommodate springs of widely differing widths. In fact, two springs 138 could be placed in a double-width housing and retainer to double the power of the motor. Moreover, similar pairs of springs could be coupled in series in each housing to permit doubling of the cable which can be unwound from the drum 16, without otherwise altering the basic concept of the invention.

Operation Generally speaking, the assembly and operation of the balance reel is probably evident from the foregoing description. Briefly, the first spring motor 83 is mounted upon the drum housing 12, substantially as described above. If an additional spring motor is desired, it is simply mounted upon and coupled with the rearwardmost motor housing, and additional motor strength is accordingly provided.

It is well known that the resistance of the spring motor to unwinding movement of the drum 16 can be altered by changing the tension upon the spring. Accordingly, after the amount of motor strength has been achieved approximately by coupling spring motors together, final tensioning adjustment is effected by appropriate rotation of the worm shaft 64, in a substantially conventional manner, which rotates the main shaft 17 and the stub shafts coupled therewith. Under normal circumstances, such adjustment can cover the necessary range of power requirements between the spring motor units of two adjacent sizes. That is, the balance reel can be adjusted for a load between a two-motor unit and a three-motor unit by appropriate adjustment of the worm 63.

The strength of the motor unit 82 can be quickly and easily reduced by removing the spring motor 8313 or by removing the motors 83A and 8313. For example, three bolts 153 are loosened and the end disk 151 is removed. The three bolts 104B, that hold the spring motor 83B upon the spring motor 83A, are loosened and the spring motor 83B is removed from the motor unit. Thereafter, the end disk 151 is mounted upon the rear side of motor 83A by means of the bolts 153, and the weakened spring unit is in condition for use, subject to the fine adjustment by the worm 63, after the cable 26 has been attached to the desired load 28. The removal of the motor 83B and the spring adjustment for the new load can all be made in a matter of minutes.

With a load 28 (FIGURE 4) supported by the cable 26, and with the balance reel 10 adjusted to support the load 28 in any selected position within the normal range of operation of the balance reel, a change in the vertical position of the load 28 can be effected by applying to said load the necessary force (usually relatively small) required to overcome the initial friction and inertia.

If downward movement of the load 28 is effected the springs 138, 138A and 138B (FIGURE 2) will be tightened, thereby tending to urge the load 28 back to its previous position. However, with the load in its new, lowered position, the cable 26 will hang tangentially from a point in the spiral groove 24 which is spaced a greater distance from the axis of the drum 16 than was the previous point of tangential departure from said drum. Thus, the load will be applying a proportionately greater torque to the drum in the unwinding direction to counteract the increased tension provided by said springs. These forces are balanced so that the load 28 will tend to remain in its new, lowered position until another force is applied thereto for the purpose of changing its vertical position.

The outer ends of the several springs 138, 138A and 138B are connected to the drum 16 by means of the spring retainers 116, 116A and 116B, which are interconnected and also connected to the hub 44, which is in turn connected to the end plate 33 of said drum. The inner ends of the springs 138, 138A and 138B are connected to the stub shafts 123, 123A and 123B, respectively, which are in turn connected to the main shaft 17 and thereby adjustably anchored upon the frame structure 11.

It can be seen that by removably connecting the inner end of the spring 138 to the hub 44, by omitting the pawl 143 and by connecting the outer end of the spring 138 to the housing 84, for example, the arrangement described above can be reversed.

Because the spring motors 83, 83A and 83B are identical and interchangeable, at least in the disclosed embodirnent, they are in a sense modular.

Although a particular preferred embodiment of the invention has been disclosed above for illustrative purposes, it will be recognized that variations or modifications of such disclosure which come within the scope of the appended claims, are fully contemplated.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A rotary device for opposing a torque applied thereto, said device having a frame structure, and torque-receiving means rotatably supported upon said frame structure, comprising:

first spring motor means having first housing means mounted upon said frame structure, first coil spring means within said first housing means and a first pair of coupling means for respectively connecting one end of said first spring means to said frame structure and the other end of said first spring means to said torque-receiving means; and

second spring motor means having second housing means, second coil spring means and a second pair of coupling means for respectively connecting one end of said second spring means to said frame structure and the other end of said second spring means to said torque-receiving means, said other end of said second spring means being alternatively connectible to that one of said first pair of coupling means connected to said torque-receiving means, said second housing means being removably connectible to either one of said frame structure and said first housing means, whereby said first and second spring motor means are alternatively (l) individually connectible and (2) connectible in parallel, between said torquereceiving means and said frame structure.

2. A rotary device according to claim 1, wherein said first pair of coupling means connects the inner and outer ends of said first spring means to said frame structure and said torque-receiving means, respectively; and

wherein said second pair of coupling means connects the inner and outer ends of said second spring means, respectively, to said frame structure through one of said first coupling means and to said torque-receiving means through the other of said first coupling means.

3. A rotary device according to claim 1, wherein said frame structure comprises a housing having shaft means supported therein;

wherein said torque-receiving means comprises drum means rotatably supported upon said shaft means and elongated flexible element means secured upon the periphery of said drum means;

wherein said first pair of coupling means includes inner and outer means connecting the inner and outer ends, respectively, of said first spring means to said shaft means and to said drum means, respectively; and

wherein said second pair of coupling means connects the inner and outer ends of said second coil spring means to said inner and outer means, respectively, of said first coupling means.

4. A rotary device according to claim 3, wherein said drum means is conical.

5. A rotary device according to claim 1, wherein said first pair of coupling means connects the inner and outer ends of said first spring means to said torque-receiving means and to said frame structure, respectively; and

wherein said second pair of coupling means connects the inner and outer ends of said second spring means, respectively, to said torque-receiving means through one of said first coupling means and to said frame structure through the other of said first coupling means.

6. In a balance reel having a drum, a drum housing, shaft means rotatably supporting said drum in said drum housing, elongated flexible element means connected to, and at least partially wound on, said drum, and adjustable motor means for balancing the torque applied to said drum by a load connected to said element means, said adjustable motor means comprising:

first and second, similar spring motor means having respectively first and second housing means and first and second coil spring means within said housing means, said first and second housing means being located outside of and axially spaced from said drum, said first housing means being attached to the drum housing and said second housing means being removably connected to said first housing means; and

inner and outer coupling means, said inner coupling means being connected between the inner ends of said first and second coil spring means and said shaft means, and said outer coupling means being connected between the outer ends of said first and second coil spring means and said drum, whereby said second spring motor means is removably connectible in parallel with said first spring motor means between said drum and said shaft means.

7. A balance reel according to claim 6, wherein said adjustable motor means includes third spring motor means having third housing means and third coil spring means, said third spring motor means being connectible in parallel with said first and second spring motor means, and said first, second and third spring motor means being interchangeable.

8. A balance reel according to claim 7, wherein a worm gear is concentrically connected to said shaft means; and

wherein a worm is rotatably supported upon said drum housing transversely of and adjacent to said shaft means, and in engagement with said gear, whereby rotation of said worm effects rotation of said shaft means and the inner coupling means connected thereto, thereby changing the tension on said coil spring means.

9. A balance reel according to claim 6, wherein said inner coupling means includes first and second stub shaft means connected to said coil spring means; and

wherein said first and second housing means, said first and second coil spring means and said first and second stub shaft means are substantially identical, respectively.

10. A balance reel according to claim 6, wherein said outer coupling means includes a pair of spaced, annular plate means in each of said first and second housing means on opposite sides of each of said first and second coil spring means, and rod means extending between each of said pairs of annular plates near their peripheries, said rod means being connected to the outer ends of said coil spring means; and

wherein said inner coupling means includes first and second stub shaft means connected to the inner ends of said first and second coil spring means, respectively, said first stub shaft means being removably and drivingly connectible to said second stub shaft means.

11. A balance reel according to claim 10, wherein said outer coupling means includes a pawl means on said rod means releasably engaging the outer ends of said first and second coil spring means; and

wherein said inner coupling means includes collar means on said stub shaft means releasably engaging the inner ends of said first and second coil spring means.

12. A balance reel according to claim 11, wherein each of said first and second housing means has a plurality of radially inwardly extending and circumferentially spaced abutments engageable by said pawl means, said pawl means being held away from said engagement by said coil spring means; and

relatively weak, resilient means urging said pawl means into a position of said engagement with said abutments for positively stopping rotation of said outer coupling means and said drum in an unwinding direction.

13. A balance reel according to claim 6, including 2. Geneva wheel mechanism mounted upon and between the drum and the drum housing for positively limiting rotational movement of said drum in both rotational directions, the limitation in one rotational direction being effected when said flexible element means is substantially completely wound upon said drum, and the limitation in the opposite rotational direction being effected when said flexible element means is substantially completely unwound from said drum.

14. A rotary device for opposing a torque applied thereto, said device having a frame structure, and torque-receiving means rotatably supported upon said frame structure, comprising:

first spring motor means having first housing means attached to said frame structure, first coil spring means within said first housing means and a first coupling means including stub shaft means for respectively connecting one end of said first spring means to said frame structure and the other end of said first spring means to said torque-receiving means; and

engaging means on said first coupling means for driving and substantially coaxial connection with second coupling means in a second spring motor means similar to said first spring motor means and attachable to the housing means thereof, whereby the spring means of said second spring motor means can be connected in parallel with the spring means of said first spring motor means.

15. A rotary device for opposing a torque applied thereto, said device having a frame structure, and torque-receiving means rotatably supported by said frame structure, comprising:

first spring motor means having first housing means mounted upon said frame structure, first coil spring means within said housing means and first inner and outer coupling means, one of said first coupling means connecting one end of said first spring means to said frame structure and the other of said first coupling means connecting the other end of said spring means to said torque-receiving means; and

second spring motor means having second housing means, second coil spring means and second inner and outer coupling means, one of said second coupling means being arranged for connecting one end of said second spring means to said frame structure and the other of said second coupling means being arranged for connecting the other end of said second spring means to said torque-receiving means, said other end of said second spring means being alternatively connectible to that one of said first pair of coupling means connected to said torque-receiving means, said second housing means being removably connectible to either one of said frame structure and said first housing means, whereby said first and second spring motor means are individually connectible and connectible in parallel to provide torque resistance between said torque-receiving means and said frame structure.

16. A rotary device according to claim 15, wherein said first and second spring motor means are removably and interchangeably connectible to said frame structure.

17. A rotary device according to claim 15, wherein said first and second housing means are removably and interchangeably connectible to either one of said frame structure and the other of said housing means.

18. 'In a balance reel having a drum, a drum housing, shaft means rotatably supporting said drum in said drum housing, elongated flexible element means connected to, and at least partially wound on, said drum, and adjustable motor means for balancing the torque applied to said drum by a load connected to said element means, the combination comprising:

first and second, similar spring motor means having respectively first and second housing means and first and second coil spring means within said housing means, said first housing means being attached to the drum housing and said second housing means being removably connected to said first housing means; and

inner and outer coupling means, one of said coupling means being connected between the inner ends of said first and second coil spring means and one of said shaft means and said drum, and the other coupling means being connected between the outer ends of said first and second coil spring means and the other one of said shaft means and said drum, whereby said second spring motor means is removably connectible in parallel with said first spring motor means to provide torque resistance between said drum and said shaft means.

19. A balance reel having a drum, a drum housing, shaft means rotatably suporting said drum and said drum housing, elongated flexible element means connected to, and at least partially wound on, said drum, and adjustable motor means for balancing the torque applied to said drum by a load connected to said element means, said balance reel comprising:

a plurality of similar spring motor means each having spring motor housing means and coil spring means within said housing means, each of said similar spring motor means being adapted to be removably attached to either the drum housing or to any of the other spring motor housing means; and

inner and outer coupling means, one of said coupling means being adapted for connection between the inner end of said coil spring means of any of said spring motor means and one of said shaft means and said drum, and the other of said coupling means being adapted for connection between the outer end of said coil spring means of any of said spring motor means and the other one of said shaft means and said drum, whereby said spring motor means can be removably connected to said drum housing or to the housing means of a similar spring motor means connected to said drum housing thereby to provide torque resistance by coupling between said drum and said shaft means, and a housing end plate adapted to be removably connected over the end of the housing means of the last spring motor means of said balance reel to provide, with the drum, drum housing and motor housing means, a complete housing for said balance reel.

20. A rotary device for opposing a torque applied thereto comprising:

a frame structure including a main shaft;

a drum rotatably mounted on said main shaft;

first spring motor means comprising rotatable spring retainer means, first coil spring means, the outer end of said first coil spring means being connected to said spring retainer means, stub shaft means supported for rotation with respect to said spring retainer means, the inner end of said coil spring means being connected to said stub shaft means, said stub shaft means and said main shaft having interfitting parts on the adjacent ends thereof for driving connection therebetween, the opposite end of said stub shaft means having an interfitting part similar to the interfitting part on said main shaft so that a second spring motor means having stub shaft means similar to said first-mentioned stub shaft means can be coupled to said first spring motor means, and interfitting drive means on adjacent parts of said spring retainer means and said drum for drivingly connecting same together, said spring retainer means having second interfitting drive means similar to and spaced from the interfitting drive means on said drum so that a second spring motor means having a spring retainer means similar to the first-mentioned spring retainer means can be drivingly connected thereto.

21. A rotary device according to claim 20, in which said interfitting parts and said interfitting drive means both include an out-of-round recess and an out-of-round projection snugly slideably fitting within its associated recess.

1 1 l 2 22. A rotary device according to claim 20, in which tainer means, said stub shaft means and said main said frame structure has a transaxial wall between said shaft being interconnected by an axially extending drum and said first spring motor means, said Wall having a out-of-round drive part and means defining an outcentral opening; of-round pocket snugly and slideably receiving said wherein a first annular hub projects axially from said 5 drive part.

2331111. sttlggtugh said central opemn and encircles said References Cited wherein a bearing is mounted on said Wall and supports UNITED STATES PATENTS said hub for rotation, said hub having an out-o f- 2072 582 3/1937 Douglass 242 107 4 round projection extending toward said firstmen- 1O 2:342:02O 2/1944 Stevens tioned spring retainer means, said first spring retainer means having an out-of-round recess in said adjacent FOREIGN PATENTS part thereof for snugly and slideably receiving said 712,240 6/1965 Canada.

projection, said first spring retainer means having a second hub similar to said first hub and projecting 15 WILLIAM S. BURDEN, Primary Examiner. from the opposite axial side of said first spring re- 

